Update plugin.sh

plugin.sh

@@ -64,6 +64,10 @@ if [[ "${PLUGIN_SKIP_UNUSED_STAGES:-}" == "true" ]]; then
     SKIP_UNUSED_STAGES="--skip-unused-stages=true"
 fi
 
+if [[ -n "${PLUGIN_SNAPSHOT_MODE:-}" ]]; then
+    SNAPSHOT_MODE="--snapshot-mode=${PLUGIN_SNAPSHOT_MODE}"
+fi
+
 # auto_tag, if set auto_tag: true, auto generate .tags file
 # support format Major.Minor.Release or start with `v`
 # docker tags: Major, Major.Minor, Major.Minor.Release and latest
@@ -112,6 +116,7 @@ fi
     ${CACHE_REPO:-} \
     ${TARGET:-} \
     ${SKIP_UNUSED_STAGES:-} \
+    ${SNAPSHOT_MODE:-} \
     ${BUILD_ARGS:-} \
     ${BUILD_ARGS_FROM_ENV:-}